1. Field of the Disclosure
The present disclosure relates to a circuit for mitigating electrostatic discharge and more specifically to mitigating the transmission of electrostatic discharges to prevent device failures.
2. Description of the Related Art
Electrostatic discharge (ESD) events are serious issues concerning the longevity and durability of integrated circuits (ICs). ESD events are caused by the familiar buildup and discharge of charges due static electricity and also through electrostatic induction, which occurs when a conductive object is exposed to an electric field. The electric field causes the distribution of charges on the conductive object to become uneven, thereby concentrating like charges which are subsequently discharged to cause an ESD event.
ICs include semiconductor materials such as silicon and insulating materials such as silicon dioxide that are patterned or deposited in specific ways to enable a given function. If either of these materials suffers damage, such as due to an ESD event, the IC may become inoperable or suffer significant loss in performance. Accordingly, ESD prevention devices are typically implemented within the IC's power/ground domain (herein “power domain”) for handing such ESD events.
Further, with the advancement of IC designs, many System-on-chips (SoCs) and other IC implementations oftentimes involve multiple subsystems and interfaces that operate in separate power domains. For example, a power domain with a 3.3V rail may service a processing core while another power domain with a 5V rail may service a Universal Serial Bus (USB) interface. In order to receive data from the interface, the processing core and interface are coupled, thereby creating a power domain boundary. Although existing ESD devices can mitigate ESD events within separate, single power domains, some ESD events are imparted from one power domain into another and subsequently cause IC failures at power domain boundaries.